Effects of Nitrogen on the Selective Dissolution of a Duplex Stainless Steel

Abstract

Nitrogen (N) has been shown to exert a beneficial influence on localized corrosion resistance of austenitic stainless steels. With duplex stainless steels (SSs), N plays a dual role of controlling the austenite to ferrite ratio and increasing corrosion resistance. In addition, on rapid cooling from high temperatures, N can form deleterious precipitates in the ferrite reducing corrosion resistance. The corrosion resistance and corrosion modes are quite different in N and non-N duplex SSs. These differences are illustrated for a 25%Cr duplex SS.